(~s)
If you refer to something as an ~, you mean that it is supposed to be a secret, but many people know about it.
It’s an ~ that the security service bugged telephones.
N-COUNT
(~s)
If you refer to something as an ~, you mean that it is supposed to be a secret, but many people know about it.
It’s an ~ that the security service bugged telephones.
N-COUNT
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012